Penicillin Production in Penicillium chrysogenum is not Dependent on the Number of Synthesis Genes

Multi-copy gene integration into microbial genomes is a conventional way to gain improved gene expression. For Penicillium chrysogenum, the fungal producer of the antibiotic penicillin, several producing strains carry multiple copies of the penicillin synthesis gene cluster. This led to the generally accepted view that high penicillin concentrations are the result of multiple copies of penicillin genes. Sandra Ziemons of Ruhr-Universität Bochum investigated P2niaD18, a production strain with only two copies of the penicillin gene cluster.

The team investigated the production, deletion and overexpression strains generated in the P. chrysogenum P2niaD18 background to determine the copy number of the penicillin biosynthesis gene cluster, study their expression, and the resulting penicillin concentration. Analysis showed that the increase in penicillin concentration did not depend on the copy number of the penicillin gene cluster.

Based on these results, the enhanced penicillin concentration does not strictly depend on the number of gene clusters. Therefore, manipulation of complex regulatory mechanisms could be another suitable way to increase penicillin synthesis.

For more on this study, read the article in BMC Biotechnology.